Sharpeners for cutting reels

ABSTRACT

A rotatable grinding disc is supported on the frame of a cutting reel for movement back and forth along a track tube of the knife cylinder. The tube is rockably mounted to provide for swinging of the grinding disc into and out of a position where the end face of the disc is engageable with one of the knives. There is means including a cam arm and mechanical linkage for transmitting rocking motion to the knife cylinder as the grinding stone progresses axially of the latter so that all portions of the cutting edge of the angled or helical knife are presented in the same relationship to the end face of the stone, and there is manual indexing to bring a new knife into a position to be sharpened.

United States Patent Primary ExaminerWilliam R. ArmstrongAttorney-Morse" & Morsell ABSTRACT: A rotatable grinding disc issupported on the frame of a cutting reel for movement back and forthalong a track tube of the knife cylinder. The tube is rockably mountedto provide for swinging of the grinding disc into and out of a positionwhere the end face of the disc is engageable with one of the knives.There is means including a cam arm and mechanical linkage fortransmitting rocking motion to the knife cylinder as the grinding stoneprogresses axially of the latter so that all portions of the cuttingedge of the angled or helical knife are presented in the samerelationship to the end face of the stone, and there is manual indexingto bring a new knife into a position to be sharpened.

PATENTEI] Jun 1 19m SHEET E [1F 4 T. R O T N w E V N ATTORNEYS PATENTEDJun 1 m:

SHEET 3 [1F 4 AT TORNEY S SI-IIARPENERS FOR CUTTING REELS BACKGROUND OFTHE INVENTION l. Field of the Invention:

The present invention relates to a sharpener for rotatable cutting reelsof the type having angled or helical knives, and is particularly suitedfor permanent or removable attachment to the frame of a forage harvestercutting reel.

2. Description ofthe Prior Art Heretofore sharpeners for cutting reelshave commonly comprised nonrotatable sharpening stones which are adaptedto be reciprocated back and forth, usually by manual action, thesharpening being done by rotating the cutting reel. In our copendingapplication Ser. No. 46,192, filed June 15, 1970, a continuation ofapplication, Ser. No. 687,528, filed Dec. 4, 1967, a sharpener isdisclosed embodying certain features in common with the sharpener of thepresent invention. In the copending case there is also means between thereel-rocking mechanism and the reel which is responsive to return of thecarriage to starting position, after sharpening of one blade has beencompleted, for automatically indexing the reel to bring another bladeinto position. This mechanism is necessarily quite complicated andfurthermore automatic indexing in addition to the automatic reel-rockingis not always desired or necessary.

SUMMARY OF THE INVENTION It is an object of the present invention toprovide an improved sharpener having improved means for supporting thegrinding stone so that it is accurately guided in its axial movement,the arrangement providing for swinging of the stone into and out ofoperative position, and the invention including relatively simplemechanism for automatically rocking the cutting reel as the rotatablegrinding stone is axially fed, whereby all portions of the knife beingsharpened are maintained in the same relationship to the stoneregardless of the angled or helical shape of the knife, said mechanismincluding a provision for simple manual indexing of the knife cylinderto bring a new knife into sharpening position after sharpening of oneknife has been completed.

A more specific object of the invention is to provide a sharpener asabove described including a supporting tube having axial track grooveswhich coact with wheels on the grinder carriage to guide the carriage inaxial movement, said tube being mounted for rotation whereby the tubewill rock to permit swinging of the grinder into and out of operativeposition, the sharpener assembly being readily removable but also beingswingable to an inoperative position so that it may remain con nectedwhile the cutting reel is being used for cutting purposes.

A further object of the invention is to provide, in a sharpener forcutting reels of the class described, an improved actuator arm andindexing hub assembly adapted for quick connection and disconnectionfrom the end of a cutting cylinder shaft, said assembly providing forautomatic transmission of rocking motion to the cutting reel duringsharpening, and also providing for manual disengagement of the hubassembly from the actuator arm assembly whereby the reel may be manuallyindexed to bring a new knife blade into position for sharpen ing, therebeing means for quickly locking the reel in its new position.

BRIEF DESCRIPTION OF THE DRAWINGS In the accompanying drawings, in whichthe same reference numerals designate the same or similar parts in allof the views:

FIG. I is a generally rear view of the sharpener, partially in section,and taken approximately on the line I-I of FIG. 2;

FIG. 2 is a transverse sectional view taken on the line 2 2 of FIG. I;

FIG. 3 is a fragmentary detail view, partially in transverse section,showing the actuator arm and indexing hub connected to the splined endof the cutting reel shaft;

FIG. 4 is a fragmentary perspective view showing the shar pening deviceattached to the frame ofa cutting reel, with the grinder tilted down andin starting position;

FIG. 5 is a fragmentary perspective view somewhat similar to FIG. 4 butshowing the grinder at the far end of a grinding pass about ready tostart a return trip;

FIG. 6 is a fragmentary perspective view showing the sharpenerassociated with the frame of a cutting reel, the grinder being tilted upto an inoperative position;

FIG. 7 is an exploded perspective view showing the principal parts whichmake up the actuator arm and indexing hub assembly; and

FIG. 8 is a fragmentary-perspective view showing a straightangled blade,the cutter being capable of sharpening such a blade as well as thehelically angled blade illustrated in FIG. 4.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring more particularlyfirst to FIG. I, the sharpener includes a baseplate 20 having endflanges 2I. L-pins 22 have threaded engagement with nuts 23 secured tothe end flanges and said pins have ends which are suitably engageablewith end plates 24 of the track tube frame, the end plates beingconnected at their lower ends by a bar 25. The end plates are alsoremovably held in assembled position by capscrews 26 (see FIG. 4), butmay be tilted on the L-pins when the capscrews are removed.

A track tube 27 is rotatably connected between the end plates 24 bymeans of bolts 28 which extend through end discs 29 having circularflanges 30. The end discs extend through circular openings in the endplates 24 and are rigidly bolted to the ends of the track tube 27 sothat the and discs rotate in the end plates 24 when the track tube isrotated. A guard 31, which is L-shaped in cross section, has endbrackets 32 which are rigidly connected to the track tube: 27 so thattheguard 31 rotates with the track tube. Also rigidly connected to one endof the track tube is an L-shaped bracket 33 to which a fitting 36 ispivoted as at 35, one end of the cam arm 34 being rigidly connected tothe fitting 36 and the other end being rigidly connected to a fitting37. The fittings .36 and 37 are also connected by a back-bracing rod 38(FIG. 6).

Mounted on shafts 39 which extendl through the track tube are sprocketwheels 40 around which an endless chain 41 is trained. One of the shaftsalso carries another sprocket wheel 42 which is connected by an endlesschain 43 with a smaller sprocket wheel 44 keyed to a shaft 45. The wheel42 is arranged to drive the juxtaposed sprocket wheel 40 and hence theendless chain 41. The shaft 45 is suitably journaled transversely of thetrack tube and has a squared end to which a crank 46 may be removablyconnected through a hole 47 in the wall of the guard 31. A chain guidebracket 48 has a slot 49 which coacts with a pin 50 projecting from oneof the chain links. Thus as the chain is caused to move throughoperation of the crank 46 the pin 50 will cause movement of the bracket48. As the pin approaches the end of a stretch and passes around thesprocket, it will move downwardly in the slot 49 so that, when it is inthe return stretch, it will cause reverse movement of the bracket. Thebracket 48 projects from a carriage 51 (FIG. 2) and the latter haslaterally projecting trunnions 52 which support rollers 53, the latterriding in the track grooves 54 of the track tube 27 (see also FIG. 5).Also rotatably supported on the carriage 51 are cam follower wheels 55which engage opposite sides of the cam arm. 34, as shown in FIG. 2 and6.

An electric motor 56 has its drive shaft 57 operating a grinding stone58. Which stone is loosely surrounded by a guard strap 59, the latterhaving its ends connected to the carriage (see FIG. 2). Secured to theback of the motor casing is a baseplate 60 having projecting eyeportions 61. An upright standard 62 on the carriage has laterallyprojecting eyes 63 and 64. Guide rods 65 are secured by setscrews toeyes of the standard 62 so that the motor and grinding stone areadjustably movable up and down on the guide rods 65. A shelf member 66projecting from the carriage supports a ratchet wheel 67 which isrigidly mounted on an adjustment rod 68, the latter having a handle 69.The ratchet wheel coacts with a suitable dog on the shelf 66. Theadjustment rod 68 has its lower portion in threaded engagement with alug 70 projecting from the baseplate of the motor. Thus, when thehandwheel 69 is turned in one direction or the other, the grinding stonewill be raised or lowered on the carriage, the ratchet wheel providingfor the holding of an adjusted position.

In FIGS. 4, and 6 is illustrated a cutter assembly of the type used inforage harvesters. It includes a suitable frame 71 having a cutting reel72 therein, with a reel shaft 73 (see FIGS. 3 and 5) which is rotatablymounted in the frame as is customary. The cutting reel includes asuitable spider 74 supporting knives 75, usually six in number. Theknives are usually helical, as is clear from FIG. 5, but the inventionis applicable to reels having angled straight knives, such as the knives75' of FIG. 8, in lieu of the helical knives. It is to be understoodthat in the claims the term angled," when used to refer to a cutterblade, means either a straight angled blade as shown in FIG. 8, or ahelically angled blade as shown in FIGS. 4, 5 and 6. Each knife has abeveled cutting edge 76.

As shown in FIGS. 4, 5, and 6, the baseplate of the sharpener issuitably bolted to the top of the main cutting head, and it is to benoted from FIG. 5 that the forward edge of the baseplate 20 has hingefittings 77 to which a hinged cover may be connected to close the knifechamber when the cutter is being used for cutting, and when thesharpener is swung to an inoperative position such as the position ofFIG. 6.

When the sharpening assembly is being used the actuator arm and indexinghub assembly must be installed. An exploded view of this assembly isshown in FIG. 7. The actuator arm 78 projects from a ring 79 which isfreely rotatable on the laterally extending portion of the shaft 73 ofthe cutting reel. This ring has circumferentially spaced indexing holes80. The indexing hub 81 is the central portion of a disc 82. The hub isformed with internal splines 83 for coaction with the splines 84 of thecutter shaft 73 (see FIG. 3). Bolted to the inner face of the hub 81 isa washer 85 having a tongue 86 which fits in the keyway of the cuttingreel shaft 73. The actuator arm ring is rotatable around the hub 81.Projecting from the outer face of the indexing hub is a. cylindricalhousing 87 for an indexing pin 88. The indexing pin is slidable androtatable in a bore of the housing 87 and has an inner end 89 adapted toengage one of the indexing holes 80 of the actuator arm ring 79 (FIG.3), the pin being normally urged into engaging position by a spring 90housed in an enlargement of the housing bore. The indexing pin 88 isfitted with a transverse pin 91 which coacts with a cam surface 92. Whenthe indexing pin is rotated in a direction to rotate the transverse pin91 in a clockwise direction or downwardly (referring to FIG. 3), thiswill withdraw the inner end 89 of the indexing pin from the indexinghole 80 against the urging of the spring 90. The spring assembly is heldin position by a threaded plug 90.

OPERATION In use of the improved device on a forage harvester, the usualbolt-on section of the knife cover is removed before the baseplate 20 isbolted in the position shown in FIG. 4. The bolt-on cover sectionusually has a coacting hinged cover which can be removed and laterconnected to the hinge fittings 77 (shown in FIG. 5) after sharpeninghas been completed and before the harvester is put back into use.

The sharpener may be swung from the inoperative position of FIG. 6 tothe operative starting position of FIG. 4 by exerting pressure in acounterclockwise direction on the carriage, which causes a rotation ofthe track tube 27.

Before installing the actuator arm and indexing hub it is necessary toremove the usual shear pin from the cutter cylinder shaft. The indexinghub and actuator arm are installed with the tongue 86 of the washer 85mating with the usual keyway in the knife cylinder shaft 73. With theindexing pin 88 of the indexing hub engaged in one of the six indexingholes of the actuator arm ring, the splines of the hub should align withthe splines of the shaft. In assembling, if the first hole does notcause alignment, the hub should be indexed to other positions untilalignment is obtained. Thereafter the tie rod 93, which has one endpivotally connected to the actuator arm 78, is connected at its otherend to the cam arm fitting 37 as at 94 (see FIGS. 1 and 5). This is aquick-connect ball-type fitting.

When the grinder is in the operative position of FIG. 4 the adjustmentwheel 69 is manipulated to lower the grinding stone 58 until its endface contacts the bevel 76 on a knife 75 which is in properly indexedposition.

With the operating crank 46 in place, it is turned slowly, the grindermotor being in operation. This will cause the grinding stone to travelin an axial direction from the position of FIG. 4 to the position ofFIG. 5, due to the pull exerted by the endless chain 41 on the carriagebracket 48. It is desirable to turn the crank at a uniform speed fastenough to avoid burning of the knife edge. As the grinding stone travelsfrom the position of FIG. 4 to the position of FIG. 5, the curvature ofthe cam arm 34 causes swinging movement of the cam arm on the pivot 35.This swinging movement acts through the tie rod 93 to cause movement ofthe actuator arm 78. Due to the fact that the hub is locked to theactuator arm ring by the indexing pin 88, swinging of the actuator arm78 causes the cutting reel to be correspondingly rocked to compensatefor the helical or angled disposition of the knife, thus maintaining thebeveled portion 76 of the knife in the same relationship with the end ofthe grinding stone 58 regardless of the position of the grinding stonein its progression axially of the cutting reel. Since the angle of theknives is from right to left, clearance is needed for the right-hand tipof the knife edge as it meets the cutter bar of the cutting assembly.The right-hand end of the cam arm is so shaped as at 95 (FIG. 6) toautomatically provide this clearance in grinding.

As cranking of the handle 46 continues, the pin 50 of FIG. 1, whichconnects the bracket 48 to the endless chain, travels down around an endsprocket to the lower stretch, sliding downwardly in the slot 49. Thisgives desirable time delay before the carriage reverses its direction ofmovement as cranking continues. The carriage will now start movingtoward the right (referring to FIG. 5), and the shape of the cam bar nowcauses counterclockwise pivotal movement of the actuator arm 78. Thispushes the hub in a counterclockwise direction to reverse the reelrocking so as to still keep the beveled portion 76 of the blades inproper relationship with the rotating grinding stone 58.

After the return stroke has been completed the indexing pin 88 isrotated in a clockwise direction (FIG. 4) or downward (FIG. 3) torelease its end 89 from the indexing hole 80. The hub may then berotated to bring the next knife into position for sharpening, theindexing pin 88 being allowed to snap into the new hole to hold theknife in indexed position for sharpening of this next blade.

After all of the knives have been sharpened, then the grinder head maybe moved to the starting position of FIG. 4, the crank 46 removed, andthe sharpening unit swung in a clockwise direction from the position ofFIG. 4 to the inoperative position of FIG. 6, such swinging beingpermitted by the rotation of the track tube 27. The knife-casing coverwhich was heretofore removed can be then connected to the hinge fittings77 and the cover swung to a closed position and suitably locked to forma guard over the knives. Before using the cutting reel for its intendedpurpose the tie rod 93 must be detached from the fitting 37 of the camarm 34 and the indexing hub and actuator arm assembly must be removedfrom the shaft 73 of the cutting reel, the cutting reel shear pin beingreinserted. The connection between the inner end of the tie rod 93 andthe fitting 37 may be a readily detachable ball and socket type or anyother detachable connection which permits adequate pivotal movement.

In the case of a forage harvester it is entirely practical to thereafterleave the sharpening unit in the inoperative position of FIG. 6 untilsharpening again becomes necessary. Suitable means may be employed toprevent the unit from jouncing during field operation. If, however, itis desired to completely remove the sharpening unit, this may be done byremoving the L-pins 22 and the capscrews 26, and lifting the sharpeningunit off of the baseplate 20, leaving the latter in position for futureuse.

From the above it is clear that a relatively simple unit has beenprovided which may, if desired, be left in place on a forage harvesterduring field use. It is also clear that with the simple actuator andindexing hub assembly the sharpener may be quickly put back intosharpening position when required. In addition, the improved deviceprovides means for easy manual indexing to bring a new knife intoposition for sharpening.

Various changes and modifications may be made without departing from thespirit of the invention, and all of such changes are contemplated as maycome within the scope of the claims.

What we claim is:

1. In combination with a cutter assembly having a frame and having arotatably mounted cutting reel provided with angled blades, each havinga cutting edge, said reel having a shaft, a rotatable sharpening stone,means including a carriage supporting said stone on the frame formovement axially of the reel in a position to act on a blade thereof, anactuator disc rotatably mounted on said reel shaft, manually operableindexing means releasably locking said actuator disc to said reel shaftin a predetermined position of rotation to bring a blade of the reelinto operative position with respect to the sharpening stone, and meansbetween said carriage and actuator disc for causing automatic rockingmovement of the reel in response to axial movement of the carriage sothat all portions of the cutting edge of an angled blade are presentedin proper edge sharpening relationship to the stone.

2. A combination as claimed in claim 1 in which the blades are helicallyangled.

3 A combination as claimed in claim 1 in which there is an indexing hubkeyed to the reel shaft, and in which the manually operable indexingmeans comprises mechanism connected to the indexing hub for releasablylocking the actuator disc in a predetermined position of rotation withrespect to said hub.

4. A combination as claimed in claim 3 in which there is an indexing pinsupport connected to said hub, and in which there is an indexing pinmovably mounted in said support, there being a circular series of holesin the actuator disc positioned to be selectively engaged by saidindexing pin.

5. A combination as claimed in claim 4 in which there is means normallyurging the indexing pin into engagement with one of the holes of theactuator disc and in which the indexing pin support has a cam surface,there being means on the indexing pin engageable with the cam surfacewhen the pin is rotated for moving the pin to a disengaged position withrespect to the actuator disc 6. A combination as claimed in claim 3 inwhich the actuator disc is rotatable around the indexing hub and has anactuator arm to which reel-rocking motion is transmitted from thecarriage.

7. In a sharpener for the knives of a cutting reel, a frame adapted tobe attached to a cutter assembly, an elongated track member rotatablymounted in said frame for rocking movement about an axis which isadapted to be disposed parallel with the axis of the cutting reel,longitudinal tracks on said elongated member, a carriage having wheelsengaging said tracks to provide for support of the carriage and formovement of the carriage axially of the elongated track member, asharpening stone supported on said carriage whereby said carriage andstone may be rocked with elongated track member into and out ofoperative position, and a cam arm having one end pivotally connected tosaid elongated track member near one end thereof for rocking movementtherewith, in which there are cam followers on the carriage engageablewith said cam arm, and in which there IS reelrocking mechanism pivotallyconnected to the other end of the cam arm.

8. A sharpener for the knives of a cutting reel as claimed in claim 7 inwhich said reel-rocking mechanism is readily disconnectable.

9. In a sharpener for the knives of a cutting reel, a frame adapted tobe attached to a cutter assembly, an elongated track member rotatablymounted in said frame for rocking movement about an axis which isadapted to be disposed parallel with the axis of the cutting reel,longitudinal tracks on said elongated member, a carriage having wheelsengaging said tracks to provide for support of the carriage and formovement of the carriage axially of the elongated track member, asharpening stone supported on said carriage whereby said carriage andstone may be rocked with the elongated track member into and out ofoperative position, and sprocket wheel and endless chain mechanism forcausing longitudinal movement of said carriage, there being shafts forsaid sprocket wheels which are supported transversely through theelongated track member.

10. In a sharpener for the knives of a cutting reel, a frame adapted tobe attached to a cutter assembly, an elongated track member rotatablymounted in said frame for rocking movement about an axis which isadapted to be disposed parallel with the axis of the cutting reel,longitudinal tracks on said elongated member, a carriage having wheelsengaging said tracks to provide for support of the carriage and formovement of the carriage axially of the elongated track member, and asharpening stone supported on said carriage whereby said carriage andstone may be rocked with the elongated track member into and out ofoperative position, in which the elongated track member is rotatablysupported between end plates, in which the means for attachment to thecutter assembly comprises a baseplate connectable with the cutterassembly, and in which there is means for detachably connecting the endplates to said baseplate.

11. In combination with a cutter assembly having a frame and having arotatably mounted cutting reel provided with angled blades, each havinga cutting edge, said reel having a shaft, a rotatable sharpening stone,means including a carriage supporting said stone on the frame formovement axially of the reel in a position to act on 'rilade thereof, anactuator disc rotatably mounted on said reel shaft, manually operableindexing means releasably locking said actuator disc to said reel shaftin a predetermined position of rotation to bring a blade of the reelinto operative position with respect to the sharpening stone, and meansbetween said carriage and actuator disc for causing automatic rockingmovement of the reel in response to axial movement of the carriage sothat all portions of the cutting edge of an angled blade are presentedin proper edge-sharpening relationship to the stone, the supportingmeans for the carriage including a rotatably mounted tube havingdiametrically opposed tracks, and the carriage having wheels engagedwith said tracks.

12. In combination with a cutter assembly having a frame and having arotatably mounted cutting reel provided with angled blades, each havinga cutting edge, said reel having a shaft, a rotatable sharpening stone,means including a carriage supporting said stone on the frame formovement axially of the reel in a position to act on a blade thereof, anactuator disc rotatably mounted on said reel shaft, indexing meansreleasably locking said actuator disc to said reel shaft in apredetermined position of rotation to bring a blade of the reel intooperative position with respect to the sharpening stone, and meansbetween said carriage and actuator disc for causing automatic rockingmovement of the reel in response to axial movement of the carriage sothat all portions of the cutting edge of an angled blade are presentedin proper edge-sharpening relationship to the stone, said indexing meanscomprising an indexing hub keyed to the reel shaft, an indexing pinsupport connected to said hub, and an indexing pin movably mounted insaid support, there being a circular series of holes in the actuatordisc positioned to be selectively engaged by said indexing pin.

1. In combination with a cutter assembly having a frame and having arotatably mounted cutting reel provided with angled blades, each havinga cutting edge, said reel having a shaft, a rotatable sharpening stone,means including a carriage supporting said stone on the frame formovement axially of the reel in a position to act on a blade thereof, anactuator disc rotatably mounted on said reel shaft, manually operableindexing means releasably locking said actuator disc to said reel shaftin a predetermined position of rotation to bring a blade of the reelinto operative position with respect to the sharpening stone, and meansbetween said carriage and actuator disc for causing automatic rockingmovement of the reel in response to axial movement of the carriage sothat all portions of the cutting edge of an angled blade are presentedin proper edge sharpening relationship to the stone.
 2. A combination asclaimed in claim 1 in which the blades are helically angled. 3 Acombination as claimed in claim 1 in which there is an indexing hubkeyed to the reel shaft, and in which the manually operable indexingmeans comprises mechanism connected to the indexing hub for releasablylocking the actuator disc in a predetermined position of rotation withrespect to said hub.
 4. A combination as claimed in claim 3 in whichthere is an indexing pin support connected to said hub, and in whichthere is an indexing pin movably mounted in said support, there being acircular series of holes in the actuator disc positioned to beselectively engaged by said indexing pin.
 5. A combination as claimed inclaim 4 in which there is means normally urging the indexing pin intoengagement with one of the holes of the actuator disc and in which theindexing pin support has a cam surface, there being means on theindexing pin engageable with the cam surface when the pin is rotated formoving the pin to a disengaged position with respect to the actuatordisc
 6. A combination as claimed in claim 3 in which the actuator discis rotatable around the indexing hub and has an actuator arm to whichreel-rocking motion is transmitted from the carriage.
 7. In a sharpenerfor the knives of a cutting reel, a frame adapted to be attached to acutter assembly, an elongated track member rotatably mounted in saidframe for rocking movement about an axis which is adapted to be disposedparallel with the axis of the cutting reel, longitudinal tracks on saidelongated member, a carriage having wheels engaging said tracks toprovide for support of the carriage and for movement of the carriageaxially of the elongated track member, a sharpening stone supported onsaid carriage whereby said carriage and stone may be rocked withelongated track member into and out of operative position, and a cam armhaving one end pivotally connected to said elongated track member nearone end thereof for rocking movement therewith, in which there are camfollowers on the carriage engageable with said cam arm, and in whichthere is reel-rocking mechanism pivotally connected to the other end ofthe cam arm.
 8. A sharpener for the knives of a cutting reel as claimedin claim 7 in which said reel-rocking mechanism is readilydisconnectable.
 9. In a sharpener for the knives of a cutting reel, aframe adapted to be attached to a cutter assembly, an elongated trackmember rotatably mounted in said frame for rocking movement about anaxis which is adapted to be disposed parallel with the axis of thecutting reel, longitudinal tracks on said elongated member, a carriagehaving wheels engaging said tracks to provide for support of thecarriage and for movement of the carriage axially of the elongated trackmember, a sharpening stone supported on said carriage whereby saidcarriage and stone may be rocked with the elongated track member intoand out of operative position, and sprocket wheel and endless chainmechanism for causing longitudinal movement of said carriage, therebeing shafts for said sprocket wheels which are supported transverselythrough the elongated track member.
 10. In a sharpener for the knives ofa cutting reel, a frame adapted to be attached to a cutter assembly, anelongated track member rotatably mounted in said frame for rockingmovement about an axis which is adapted to be disposed parallel with theaxis of the cutting reel, longitudinal tracks on said elongated member,a carriage having wheels engaging said tracks to provide for support ofthe carriage and for movement of the carriage axially of the elongatedtrack member, and a sharpening stone supported on said carriage wherebysaid carriage and stone may be rocked with the elongated track memberinto and out of operative position, in which the elongated track memberis rotatably supported between end plates, in which the means forattachment to the cutter assembly comprises a baseplate connectable withthe cutter assembly, and in which there is means for detachablyconnecting the end plates to said baseplate.
 11. In combination with acutter assembly having a frame and having a rotatably mounted cuttingreel providEd with angled blades, each having a cutting edge, said reelhaving a shaft, a rotatable sharpening stone, means including a carriagesupporting said stone on the frame for movement axially of the reel in aposition to act on a blade thereof, an actuator disc rotatably mountedon said reel shaft, manually operable indexing means releasably lockingsaid actuator disc to said reel shaft in a predetermined position ofrotation to bring a blade of the reel into operative position withrespect to the sharpening stone, and means between said carriage andactuator disc for causing automatic rocking movement of the reel inresponse to axial movement of the carriage so that all portions of thecutting edge of an angled blade are presented in proper edge-sharpeningrelationship to the stone, the supporting means for the carriageincluding a rotatably mounted tube having diametrically opposed tracks,and the carriage having wheels engaged with said tracks.
 12. Incombination with a cutter assembly having a frame and having a rotatablymounted cutting reel provided with angled blades, each having a cuttingedge, said reel having a shaft, a rotatable sharpening stone, meansincluding a carriage supporting said stone on the frame for movementaxially of the reel in a position to act on a blade thereof, an actuatordisc rotatably mounted on said reel shaft, indexing means releasablylocking said actuator disc to said reel shaft in a predeterminedposition of rotation to bring a blade of the reel into operativeposition with respect to the sharpening stone, and means between saidcarriage and actuator disc for causing automatic rocking movement of thereel in response to axial movement of the carriage so that all portionsof the cutting edge of an angled blade are presented in properedge-sharpening relationship to the stone, said indexing meanscomprising an indexing hub keyed to the reel shaft, an indexing pinsupport connected to said hub, and an indexing pin movably mounted insaid support, there being a circular series of holes in the actuatordisc positioned to be selectively engaged by said indexing pin.